Spectrally sensitized photographic emulsions

ABSTRACT

A SILVER HALIDE LIGHT-SENDITIVE PHOTOHRAPHIC EMULSION CONTAINING AT LEAST ONE SENSITIZING DYE REPRESENTED BY THE FOLLOWING FORMULA I:   (-Z1-N(+)(-R1)=)&gt;C-CH=C(-R)-CH=C&lt;(-Z2-N(-R2)-)   (X1(-))(N-1)   IN WHICH R IS A HYDROGEN ATOM OR AN ALKYL GROUP HAVING FROM 1 TO 4 CARBON ATOMS; R1 AND R2, WHICH MAY BE THE SAME OR DIFFERENT, EACH REPRESENTS AN ALKYL GROUP, AN ALLYL GROUP AND AN ALKYL GROUP SUBSTITUTED BY HYDROXY, CARBOXY, SULFO OR MIXTURES THEREOF, AT LEAST ONE OF R1 AND R2 BEING A SUBSTITUTED ALKYL GROUP; Z1 IS A NON-METALLIC ATOMIC GROUP NECESSARY TO COMPLETE A HETEROCYCLIC NUCLEUS OF THE NAPHTHOTHIAZOLE, NAPHTHOSELENAZOLE OR NAPHTHOXAZOLE SERIES; Z2 IS A NON-METALLI GROUP NECESSARY TO COMPLETE A NUCLEUS OF THE NAPHTHOSELENAZOLE, NAPHTHOXAZOLE, NAPHTHOIMIDAZOLE OR BENZIMIDAZOLE SERIES; X1-IS AN ACID ANION AND N IS 1 OR 2, AND AT LEAST ONE SENSITIZING DYE REPRESENTED BY THE FOLLOWING FORMULA II:   (-Z3-N(+)(-R3)=)&gt;C-CH=C(-R5)-CH=C&lt;(-Z4-N(-R4)-)   (X2(-))(M-1)   IN WHICH R5 IS AN ALKYL GROUP HAVING FROM 1 TO 4 CARBON ATOMS; R3 AND R4, WHICH MAY BE THE SAME OR DIFFERENT, EACH REPRESENTS AN ALKYL GROUP, AN ALLYL GROUP AND AN ALKYL GROUP SUBSTITUTED BY HYDROXY, ALKOXY, CARBOXY, SULFO OR MIXTURES THEREOF; A3 AND Z4, WHICH MAY BE THE SAME OR DIFFERENT, EACH REPRESENTS A NON-METALLIC ATOMIC GROUP NECESSARY TO COMPLETE A BENZOTHIAZOLE OR A BENZOSELENAZOLE NUCLEUS, WHICH MAY BE SUBSTITUTED BY HALOGEN, PHENYL, ALKOXPHENYL, HYDROXYPHENYL, CARBOXYPHENYL, AN ALKYL HAVING FROM 1 TO 4 CARBON ATOMS, HYDROXYL, ALKOXY, CARBOXYL, CARBOXYLIC ACID ESTER, CARBAMOYL OR ALKYL CARBAMOYL GROUPS; X2 IS AN ACID ANION AND M IS 1 OR2.

July 25, 1972 KEISUKE sHlBA ETAL 3,679,428

SPECTRLLY SENSITIZED PHOTOGRAPHIC EMULSIONS Filed July 23, 1970 .vh Y v4". 3 v Y Vv/\ I TM /2 l.. y/ X 440 480 520 560 600 640 680 WAVELENGTH (nm) INVENTORS KEISUKE SHIBA MOTOHIKO TSUBOTA AKIRA SATO, TADASHI IKEDA AKIRA osAwA l BY SZ 1 W United States Patent O1 lice 3,679,428 Patented July 25, v1972 3,679,428 SPECTRALLY SENSITIZED PHOTOGRAPHIC EMULSIONS Keisuke Shiba, Motohiko Tsubota, Akira Sato, Tadashi Ikeda, and, Akira Ogawa, Kanagawa, Japan, assignors to Fuji Photo Film Co., Ltd., Kanagawa, Japan Filed July 23, 1970, Ser. No. 57,607 Claims priority, application Japan, July 23, 1969, 44/58,180 Int. Cl. G03c 1/08 U.S. Cl. 96-124 6 Claims ABSTRACT F THE DISCLOSURE A silver halide light-sensitive photographic emulsion containing at least one sensitizing dye represented by the following Formula I:

(Formula I) Z1` R A l l C-CH=(l}-CH=C i `-1``1/ (X1-)n.1 R1 Rz in which R is a hydrogen atom or an alkyl ygroup having from 1 to 4 carbon atoms; R1 and R2, which may be the same or different, each represents an alkyl group, an allyl group and an alkyl group substituted by hydroxy, carboxy, sulfo or mixtures thereof, at least one of R1 and R2 being a substituted alkyl group; Z1 is a non-metallic atomic group necessary to complete a heterocyclic nucleus of the naphthothiazole, naphthoselenazole or naphthoxazole series; Z2 is a non-metallic group necessary to complete a nucleus of the naphthoselenazole, naphthoxazole, naphthoimidazole or benzimidazole series; X1- is an acid anion and n is 1 or 2, and at least one sensitizing dye represented by the following Formula Il:

in which R is an alkyl group having from l to 4 carbon atoms; R3 and R4, which may be the same or different, each represents an alkyl group, an allyl group and an alkyl group substituted by hydroxy, alkoxy, carboxy, sulfo or mixtures thereof; Z3 and Z4, which may be the same or dilerent, each represents a non-metallic atomic group necessary to complete a benzothiazole or a benzoselenazole nucleus, which may be substituted by halogen, phenyl, alkoxyphenyl, hydroxyphenyl, carboxyphenyl, an alkyl hafving from l to 4 carbon atoms, hydroxyl, alkoxy, carboxyl, carboxylic acid ester, carbamoyl or alkyl carbamoyl groups; X2 is an acid anion and m is 1 or 2.

BACKGROUND OF 'IHE INVENTION Field of the invention This invention relates to a spectrally sensitized silver halide photographic emulsion and more particularly, it is concerned with a high sensitivity silver halide photographic emulsion which is supersensitized, by the use of a combination of at least two sensitizing dyes over the absorption light wavelength region of each of the sensitizing dyes.

Description of the prior art Ordinarily, conventional photographic light-sensitive materials should be sensitized with a suitable spectral sensitivity over the whole visible wavelength region. As a technique for making such a light-sensitive material, it is well known to add a sensitizing dye to a silver halide photographic emulsion to thus expand its sensitive wavelength region to longer wavelength regions. 'This phenomenon is termed spectral sensitization.

The spectral sensitization over the visible region is required for light-sensitive materials for photography in general, but having a high spectral sensitivity up to very long wavelengths is not always preferred from the viewpoint of tone reproduction. Two or more sensitizing dyes are generally used in combination in order to obtain the most suitable distribution of spectral sensitivity. However, the spectral sensitivity obtained in the case of using two or more sensitizing dyes in combination to regulate the spectral sensitivity distribution is often lower than in the case of using each of them individually.

The spectral sensitizing action is alfected not only by the chemical structure of the sensitizing dye but also by the properties of the silver halide emulsion employed, for example, the crystal habit of the silver halide line crystals, the particle size, the halogen composition, the hydrogen ion concentration and the silver ion concentration. Furthermore, additives present in the emulsion, such as, for example, inhibitors, stabilizers, sensitizers, hardeners, binders, precipitators, plasticizers, color formers and photographic dyes, have many influences thereupon, many of them acting so as to weaken the special sensitizing action.

In the special case, however, the spectral sensitizing action obtained by adding one sensitizing dye is superadditively strengthened by also adding therewith another sensitizing dye or organic compound, in particular, an aromatic compound. The action of this type is known as supersensitization. The use of a cyanine dye alone scarcely gives a maximum sensitivity over relatively long wavelengths, such as 625 mm. to 640 mm.

=It is therefore an object of the present invention to nd the spectral sensitization capable of raising the spectral sensitivity of a photographic light-sensitive material, in particular, to a wavelength region of 625 to 640 mm.

It is another object of the present invention to provide a spectral sensitization technique whereby a stable spectral sensitivity and spectral sensitivity distribution are given immediately after addition of two or more sensitizing dyes to a silver halide emulsion. Such a technique is very important for improving the productivity in making photographic light-sensitive materials.

Other objects and advantages will be apparent from the following description.

SUMMARY OF THE INVENTION The present inventors have found that the above-mentioned objects can favorably be accomplished by providing a silver halide light-sensitive photographic emulsion having incorporated therein at least one sensitizing dye represented by the following general Formula I and at least one cyanine dye represented yby the following general Formula 1I:

(General Formula I) wherein R represents a hydrogen atom or a lower alkyl group, such as methyl or ethyl; R1 and R2, which may be the same or different, are selected from groups of the alkyl series, such as alkyl .groups (e.g., methyl, ethyl and propyl), allyl groups and substituted alkyl groups (e.g.,

2-hydroxyethyl, carboxymethyl, 3-carboxypropyl, 3-sulfopropyl, 4-sulfobuty1, -sulfoisobutyl, and 2-hydroxy-3- sulfopropyl groups), at least one of R1 and R2 being a substituted alkyl group of the type indicated; Z1 represents a non-metallic atomic group necessary to complete a heterocyclc nucleus of the naphthothiazole series (e.g., a-naphthothiazole, -naphthothiazole, 5methoxy naphthothiazole, S-ethoxy--naphthothiazole, 8-methoxya-naphthothiazole, 7 methoxy a naphthothiazole), the naphthoselenazole series (e.g., a-naphthoselenazole or naplithoselenazole), or the naphthoxazole series (e.g., anaphthoxazole or -naphthoselenazole); Z2 represents a non-metallic atomic group necessary to complete a heterocyclic nucleus of the naphthoxazole series (e.g., a-naphthoxazole or -naphthoxazole), the naphthoimidazole series (e.g., a-naphthoimidazole or -naphthoimidazole) or the benzimidazole series (e.g., 3ethyl-5,6dichloro s benzimidazole, 3 ethyl-5-ethylsulfonyl-G-triuoromethylbenzimidazole, 3 hydroxyethyl 5 cyano-6-bromobenz imidazole, 3-acetoxypropyl 5 morpholinosulfonyl-benzimidazole, 3-propyl 6 ethylcarbamoyl-benzimidazole); X1- represents an acid anion usually employed in the field of sensitizing dyes, such as a halogen ion, perchloi'ate, thiocyanate, benzenesulfonate, p-toluene sulfonate, ethylsulfate, a methylsulfate ion, and the like and n represents 1 or 2.

(General Formula. II)

'wherein R5 represents a lower alkyl group, such as ethyl or butyl; R3 and R4, which may be the same or dilerent, each represents groups of the alkyl series, such as alkyl groups (e.g., methyl, ethyl and butyl), allyl groups and substituted alkyl groups (e.g., Z-,hydroxyethyL Z-methoxyethyl, carboxymethyl, 3-carboxypropyl, 4-carboxybutyl, 3- sulfopropyl, 4-su1fobutyl, 3-sulfoisobutyl, 2-(3-sulfopropoxy)ethyl and 2hydroxy3sulfopropyl); Z3 and Z4, which may be the same ordiiferent, each represents a non-metallic atomic group necessary to complete a benzothiazole or a benzoselenazole nucleus which may be substituted by a group capable of promoting the formation of the J-aggregate, for example, a halogen atom such as chlorine or bromine, a phenyl group, a substituted phenyl group such as p-methoxy phenyl, o-hydroxyphenyl, pcarboxyphenyl, a lower alkyl group (such as methyl or ethyl), a hydroxyl group, an alkoxy group such as methoxy, a carboxyl group, a carboxylic acid ester (such as carboxymethyl or carboxyethyl), a carbamoyl group or an alkyl carbamoyl group; X2- represents an acid anion usually employed in the -eld of sensitizing dyes, such "as halogen, perchlorate, benzenesulfonate, thiocyanate, p-toluene sulfonate, rnethylsulfate, ethylsulfate and the like, and m represents l or 2.

BRIEF DESCRIPTION OF THE DRAWINGS The gure represents spectrograms of samples containing a dye of Formula I, a dye of Formula II and a combination thereof, respectively.

DETAILED DESCRIPTION OF THEl PREFERRED EMBODIMENTS The most important features of the present invention are that, lin the sensitizing dye represented by Formula I, the nitrogen atom in the cyanine dye nuclei consisting of the naphthothiazole, naphthoselenamle, naphthoxazole or naphthoimidazole nucleus is substituted by at least one substituted Ialkyl group as described above, and that the cyanine dye represented by Formula II is liable to form a relatively strong J-aggregate. The supersensitizing action over the whole wavelength region which the dyes absorb is obtained and the spectral sensitivity distribution is regulated relatively optional by the use of, in combination, the sensitizing dye characterized by the chemical structure of Formula I and the cyanine dye represented by Formula II in suitable amounts. In particular, the spectral sensitivity within a wavelength region of 625 mm. to 640 mm. can be raised. A further feature of the presentrinvention consists in the advantage that theV supersensitization given by the sensitizing dye of Formula I'serves to markedly improve the stability and reproducivity of the spectral sensitivity obtained.

The sensitizing dyes of the present invention are dissolved in .an aqueous solution or in a water-soluble organic solvent such as methanol, ethanol, acetone, methyl Cellosolve or pyridine and then added to a silver halide emulsion separately or as a mixture thereof. lStirrng by ultrasonic Waves may be applied during the dissolving of the' sensitizing dyes. The amount of addition, order of addition land addition procedure may be varied with the production process of the light-sensitive material. The amount of Vaddition of the sensitizing dyes is preferably from 1 10 mole to 5 X10-4 mole per mole of silver halide, the molar n is coated onto a suitable support, for examle, a cellulose derivative lm, a polyethylene terephthalate lm, a polycarbonate film, baryta paper, resin coated paper, synthetic paper, resin laminated paper or a glass sheet.

Examples of the sensitizing dyes -according tothe present invention are given below, these compounds being merely illustrative 'and not limiting in nature.

Sensitizing dyes represented by general Formula I:

(H2):S03HN(C2H5) Cyanine dyes represented by general Formula II:

6 Sensitizing dyes represented by Formulae I and II were separately dissolved in methanol to give a predetemined concentration (shown in Table I). A predetermined amount (shown in Table I) of each of the sensitizing dye H Co 0 a l/ N OCH solutions was added to the emulsion with agitation. After H minute, 7 ml. of each emulsion was applied to a glass Ems o i 5 sheet of cabinet size and dried to obtain a sample. (HC) s s IOne of the samples, which was then cut, was subjected (IlzHs to optical wedge exposure through a K-12 yellow filter C=CHC=CH I 10 (trademark) and a K-7 red tilter (trademark) made by COOH Fuji Photo Film Co., Ltd., using an actinometer having a i light source Whose color temperature is converted into 5400 K. by applying a David-Gibbson conversion lter am HHCH to a light source of a color temperature of 2666 K. The S05 15 other sample was exposed to obtain a spectrogram by the (HD) se Se use of a spectograph of the diffraction grating type (GR- 02H5 2 [trademark] made by Narumi Co.).

C CH= CH C 'Ihe rst sample was then developed with a developer C1 1 having the following composition at 20 C. for 10 min.

N utes and then subjected to stopping, xing and water washo H o N ing to obtain a strip whose density was measured -using HS a ms 3 a an S-type densitometer (trademark) made by Fuji Photo (HE) Film Co., Ltd., to thus obtain the yellow lter sensitivity S C H S "(Sy), red filter sensitivity (Sr) and predetermined maximum sensitivity wavelength (Smm), respectively. The

C=CH =CHC standard point of optical density to determine the sensi- C1 C 0NHC2H5 tivity is at a point of (fog-+0.20).

Composition of developer:

HRCHIOH 1' 2m Water (50 C.) ml-- 750 The sensitizing dyes represented by Formulae I and II Metol g 2 may be synthesized in any known manner. For example, Anhydrous sodium sulte g 100 dyes IA, IB, IIA, IIB, IIC, IID and IIE can be readily 4Hydroquinone g-- 5 synthesized by the methods disclosed in U.S. Pat. No. Borax g y 2 2,503,776, German Pats. Nos. 929,080 and 1,072,765 and Water to make 1000 ml.

TABLE I Amount of Amount of methanol methanol Relative sensitivity 1156111111. used, m1. Sw: Test number Dye (mol conc.) Dye (m0100110.) Sy Sr Fog (mm.)

10 (5x10-4) 191 85 0.12 620 1--'.-:.: IA 20 100 100 0.15 620 85 90 0.16 620 56 63 0.12 645 2 11A 113 113 0.12 650 20 11a 115 0. 14 650 20 (5x10-4) 5 (1x10-2) 180 160 0.12 630 anrnnn.-- IA 20 10 180 160 0. 12 640 20 20 180 160 0.14 645 20 (5x10-4) 5 (1x10-3) 13o 130 0.12 630 4--:.: IA 20 }II 10 167 145 0.13 630 20 20 183 150 0.14 640 10 (1X103) 25 90 0. 10 645 5 M A w- }IIB l 20 125 120 0.10 645 40 135 130 0.12 650 10 (5x10-4)} 9o 90 0.11 624 6--'.--;: IB 20 105 100 0.12 624 40 110 100 0.13 624 ---i- 2. 5 (1x103) 60 70 0.11 656 7 -f f l[11D 10 110 110 0.12 666 20 120 115 0. 12 660 2o (5x10-4) 5 (1x10-a) 170 160 0.12 630 8..-..-.:.--.- 1B Il 20 }IID 1o 175 175 0.14 650 20 2o 185 175 0.14 650 20 (5x10-4) 5 (5x10-4) 110 105 0.12 625 9 IB 20 }IIC 10 125 11s 0.12 630 20 20 130 126 0.13 650 5 (5X104) 61 93 0.09 630 10 FIC 10 s0 100 0.12 630 20 74 79 0.14 630 10 (1x10-3) 200 132 0.09 61s 11 IC 20 226 132 0.14 61s 40 146 71 0. 14 61s 20 (1x10-)} 5 (5x10-4) 226 150 0.16 620 12 -1-..- IC 20 IIE 10 250 155 0.16 620 20 300 180 0.25 620 5 (5x10-4) 50 60 0. 0s 62a n }IIE il 10 50 70 0. 08 623 20 50 75 0. 09 623 dye IC can be readily synthesized by the methods disclosed in British Pats. Nos. 776,050 and 979,251.

EXAMPLES The resulting spectrograms are shown in FIG. l, wherein curve 1 is a spectrogram of the sample obtained by adding 20 ml. of sensitizing dye (IA) of No. 1 in Table I;

curve 2 is va spectrogram of the sample obtained by adding 10 ml. of sensitizing dye (IIA) of No. 2 in Table I; and curve 3 is a spectrogram of the sample obtained by adding a mixture of 20 ml. of dye (IA) and 10 ml. of dye (IIA) according to the present invention.

What is claimed is: f 1. A silver halide light-sensitive photographic emulsion containing at least one sensitizing dye represented by the following Formula I: y

in which R is a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; R1 and R2, which may be the same ondiiferent, each represents/an alkyl group, an allyl group and an alkyl group substituted by hydroxy, carboxy, sulfo or mixtures thereof, at least one of R1 and R2 being a substituted alkyl group; Z1 is a Lnon-metallic` atomic group necessary to` complete a heterocyclic nucleus of the naphthothiazole, naphthoselenazole or naphthoxazole series; Z2 is a non-metallic group necessary to complete a nucleus of the napthoselenazole, naphthoxazole, naphthoimidazole or benzimidazole series; X1 is an acid anion and n is 1 or 2, and at least one sensitizing dye represented by the following Formula II:

, which may be substituted by halogen, phenyl, alkoxyphenyl, hydroxyphenyl, carboxyphenyl, an alkyl having from 1 to 4 carbon atoms, hydroxyl, alkoxy, carboxyl,

carboxylic acid ester, carbamoyl or alkyl carbamoyl groups; X1 is an acid anion and m -is l or y2. i

2. A silver halide light-sensitive photographic emulsion as in claim 1, wherein said sensitizing dyes represented by Formulae I and II are, respectively,

3. The silver halidelight-sensitive photographic emulsion as in claim 1, wherein said sensitizing dyes represented by Formulae I and II are, respectively,

and

in which R is a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; R1 and R1, which may be the same or diterent, each represents analkyl group, an allyl group and an alkyl group substituted by hydroxy, carboxy,` sulfo or mixtures thereof, at least one of R1 and R2 being a substituted alkyl group; Z1 is a non-metallic atomic group necessary to complete a heterocyclic nucleus of the naphthothiazole, or naphthoselenazole series; Z1 is a non-metallic group necessary to complete a nucleus of the naphthoselenazole, naphthoimidazole or benzimidazole series; X1- is an :acid anion and n is 1 or 2, and at least one sensitizing dye represented by the following Formula II:

in which R5 is an alkyl group having from l to 4 carbon atoms; R3 and R1, each represents a member selected from the group consisting of sulfo alkyl and hydroxyalkyl groups; Z3 and Z4, which may be the same or different, each represents a non-metallic atomic group necessary to complete a benzothiazole or a benzoselenazole nucleus, which may be substituted by halogen, phenyl, Aalkoxyphenyl, hydroxyphenyl, carboxyphenyl, an alkyl having from l to 4 carbon atoms, hydroxyl, alkoxy, carboxyl, carboxylic acid ester, carbamoyl or alkyl carbamoyl groups; X1 is an acid anion and m is 1 or 2.

References Cited UNITED STATES PATENTS 3,463,640 8/1969 Ficken et al. 96-124 3,459,553 8/ 1969 Walworth 96-124 3,338,714 8/ 1967 Ficken et al. 96-124 3,527,641 9/ 1970 Nakazawa et al 96-124 3,573,920 4/ 1971 Hiller 96-124 OTHER REFERENCES n Ser. No. 57,766, tiling date July 23, 1970, by Nakazawa et al.

NORMAN G. TORCHIN, Primary Examiner E. C. KIIMLIN, Assistant Examiner U.S. Cl. X.R. 

